We present a novel, non-contact, on-wafer device characterization method covering both THz (300 GHz-3 THz) and mmW bands (60-300 GHz). Unlike existing contact probes which rely on fragile tips and physical contact with the device on the chip, the new non-contact probe setup is based on radiative coupling of vector network analyzer test ports into the coplanar waveguide environment of monolithic devices and integrated circuits via planar, on-chip, broadband antennas. The on-chip antennas act as 'virtual' probe-tips on the test wafer and connect to the device through optimized, impedance matched coplanar waveguide (CPW) lines. Proof-of-concept validation is presented for the 325-750 GHz band using WR2.2 and WR1.5 frequency extender modules and a standard vector network analyzer as the backend. Owing to the non-contact nature, these new probes are free from wear/tear and fragility issues. More importantly, they are low cost and can be easily scaled beyond 900GHz where there is no existing solution for on-wafer device and integrated circuit testing.